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Hot wax dipping of
beehive componentsfor preservation and sterilisation
A report for the Rural Industries Research and
Development Corporation
By Russell Goodman Institute for Horticultural
Development Agriculture Victoria Knoxfield
May 2001
RIRDC Publication No 01/051
RIRDC Project No. DAV-167A
ii
2001 Rural Industries Research and Development Corporation and the Department of Natural Resources and
Environment
All rights reserved
ISBN 0 642 58273 4
ISSN 1440-6845
Hot wax dipping of beehive components for preservation and sterilisation
Publication No. 01/051
Project No. DAV-167A
The views expressed and the conclusions reached in this publication are those of the author and not necessarily
those of the persons consulted. RIRDC shall not be responsible in any way whatsoever to any person who
relies in whole or in part on the contents of this report.
Disclaimer
This publication may be of assistance to you but the State of Victoria and its employees and the Rural Industries
Research and Development Corporation do not guarantee that the publication is without flaw of any kind or is
wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other
consequence which may arise from you relying on any information in this publication.
This publication is copyright. However, RIRDC encourages wide dissemination of its research, providing the
Corporation is clearly acknowledged. For any other enquires concerning reproduction, contact the
Communications Manager on phone 02 6272 3186.
Researcher Contact Details
Russell Goodman
Institute for Horticultural Development
Private Bag 15
SOUTH EAST MAIL CENTRE VIC 3176
Phone: 03 9210 9222
Fax: 03 9800 3521
Email: [email protected]
RIRDC Contact Details
Rural Industries Research and Development Corporation
Level 1, AMA House
42 Macquarie Street
Barton ACT 2600
PO Box 4776
KINGSTON ACT 2600
Phone: 02 6272 4539
Fax: 02 6272 5877
Email: [email protected]
Website: http://www.rirdc.gov.au
Published in May 2001
Printed on environmentally friendly paper by Canprint
iii
Foreword
In July 1998, a national honey bee disease workshop was convened to developed suitable management
programs to control and reduce the level of the notifiable honey bee brood disease, American Foulbrood.
One of the recommendations arising from the workshop was that the use of disease barrier management
systems in apiaries should be encouraged.
In addition to barrier management systems, there has also been a growing interest in the apiary industry
about the use of hot wax dipping to sterilise beehive components originating from hives infected with
American Foulbrood disease. A project was funded to develop beekeeper focused guidelines regarding
these two management practices.
This publication considers best practice for hot wax dipping of beehive components for preservation and
for the prevention and control of American Foulbrood disease.
This project was funded from industry revenue which is matched by funds provided by the Federal
Government.
This report, a new addition to RIRDC’s diverse range of 700 research publications, forms part of our
Honeybee R&D program, that aims to support innovative and focused research and development
projects which will contribute to the productivity and profitability of the Australian beekeeping industry.
Most of our publications are available for viewing, downloading or purchasing online through our
website:
• downloads at www.rirdc.gov.au/reports/Index.htm
• purchases at www.rirdc.gov.au/eshop
Peter Core
Managing Director
Rural Industries Research and Development Corporation
iv
Acknowledgments
The author appreciates the contributions made by a number of apiarists towards this manual. Their
contribution in terms of sharing their experiences and knowledge of hot wax dipping of beehive
components has been invaluable. Their time and effort is greatly appreciated.
The author thanks the following apiarists:
Howard Brown, Seymour, Victoria
Norm Collins, Kangaroo Flat, Victoria
Geoff Cotton, Keith, South Australia
John Curran, Puckapunyal, Victoria
John Edmonds, Mt Duneed, Victoria
John McMonigle, Wangaratta, Victoria
John and Kieren Sunderland, Dubbo, New South Wales
Glen Watson, Devenish, Victoria.
The author also thanks:
Brad Styles, Fire Officer, Country Fire Authority, Boronia, Victoria for information on fire
prevention and control.
Frank Howard, Office of Gas Safety, Melbourne, for information on safety handling of bottled
gas.
David Morton, Dussek Campbell, Victoria for information about flash points of waxes.
v
Contents
Foreword ............................................................................................................................... iii
Acknowledgments .................................................................................................................iv
1. Introduction .................................................................................................................... 1
2. Preservation of wooden hive parts ................................................................................. 4
3. Safety............................................................................................................................. 7
4. Fire safety ...................................................................................................................... 9
5. Waxes for dipping ........................................................................................................ 12
6. Hot wax dipping for preservation.................................................................................. 14
7. Hot wax dipping for sterilisation.................................................................................... 19
8. Vats for hot wax dipping............................................................................................... 21
9. Paints and painting....................................................................................................... 26
10. References................................................................................................................... 28
1
1. Introduction
Introduction Welcome to the hot wax dipping manual for apiarists.
What is hot wax dipping? A definition
It is the placement of various beehive components, or parts, in hot
molten wax.
The term ‘dip’ means a brief immersion into a liquid.
However, when apiarists dip their hive parts in molten hot wax, it
is usually for periods of up to 15 minutes depending on the reason
for which the dipping process is being used.
Purpose of dipping hive
components
There are two reasons why apiarists hot wax dip hive parts. They
are to:
• preserve wooden hive parts so that they are protected from the
effects of weather, fungi and other causes of decay
• sterilise hive parts salvaged from hives infected with the honey
bee brood disease, American foulbrood.
Not all hive parts can be hot wax dipped.
Photo 1. Some examples of beehive material that may be hot wax
dipped.
Effectiveness of wax
dipping
Several apiarists have indicated to the author that when hot wax
dipping is done well, the waxed items will last for many years.
There is little documented information about the effectiveness of
hot wax dipping as a preservative of hives.
Some consider that only a limited degree of protection is gained
because the process is largely a surface treatment and means of
keeping timber drier (Williams 1980). On the other hand,
Matheson (1980) indicates that the process provides excellent
results. Some writers have quoted research conducted by Kalins
and Detroy (1984) to indicate that hot wax dipping is ineffective
because decay was found in dipped hive bottom boards within three
2
and a half years of treatment. However, the timber was treated
with a paintable water repellent (paraffin wax and varnish in
mineral spirits) and the results should not be compared with the
effectiveness of hot wax dipping.
The key to successful hot wax dipping is to have the molten wax as
hot as possible, but not exceeding the safety limits detailed later in
this manual. It is also essential that the wood being dipped is well
heated throughout to ensure maximum penetration of the wax into
the timber. The process should not be hurried by dipping for only
a short period of time.
Safety first!
Hot wax dipping is a dangerous process if safety precautions are
not followed.
Severe burns to the operator can result if care is not taken.
Fire may also result. Remember that wax is flammable. Keep the
temperature of the molten wax below the stated flashpoint
temperature (see section ‘Safety first’).
When to wax dip Wax dipping can be done at any time of the year, subject to the
precautions listed below.
Dipping is often conducted during the winter months when the
active beekeeping season has finished and apiarists have time to
attend to maintenance of hive material and other equipment. A
small amount of wax may drain from the dipped item after it is
removed from the vat. If the draining wax congeals and forms
beads on the surface of the dipped item, the wood has probably not
been heated enough. Very little wax drains from timber that has
been well heated and is very hot towards its centre. As the timber
begins to cool, most or all of the liquid wax on the surface is drawn
or sucked into the timber. Because the timber is so hot, any wax
that is not drawn into the timber will remain liquid and will readily
drain away before temperatures cool to the degree that beading
might occur.
Precaution against fire Observe all fire safety regulations applicable in your State or
Territory. Regulations control the use of fire on days of ‘Total Fire
Ban’ and during declared fire danger periods.
Some statistics Approximately 30 to 50 beehive supers (boxes) can be dipped in
one day.
One apiarist has calculated that a full depth beehive super will
absorb approximately 30 grams of wax.
Information in this manual Much of the information presented in this manual has been given
3
freely by a number of Australian apiarists willing to share their
knowledge and experiences. Some information has been sourced
from overseas beekeeping journals and similar publications.
The information in this manual is presented as ‘best practice’ in
use at the time of writing. Readers are encouraged to identify and
adopt measures to improve the safety of the hot wax dipping
process for their own individual situations.
4
2. Preservation of wooden hive parts
The need to protect hives Damp timber is prone to decay.
Most Beehives in Australia are made from pine. This timber has
little durability and needs protection if it is to have a useful
working life. It will soon begin to decay if left unprotected from
the effects of weather outside the hive and the moisture that occurs
at certain times of the year inside the hive.
Apiarists have found that even when hive components items such
as pine boxes and clearer boards are painted, dry rot can quickly
reduce their useful life to only two or three years. This is
particularly true of hive components that have been cut from pine
before the timber has had time to adequately mature.
It is extremely costly and time consuming to replace boxes and
other wooden hive parts that have had their useful life prematurely
shortened because steps were not taken to preserve them.
Photos 2 and 3. Examples of wood decay in a clearer board (left)
and hive (right).
Apiarists weather-proof and preserve hive components in a number
of ways. The majority of hives are painted, but sometimes other
treatments are used, either with painting or instead of painting.
This manual details one of these treatments known as hot wax
dipping.
Cause of decay Decay in wood is caused by fungi.
Fungi have one major requirement, moisture, before they can attack
wood and cause decay and rot. Wood that remains damp will
support decay organisms.
In contrast, wood that has less than 20% moisture content will not
support decay organisms (Robinson and French 1986). These facts
were confirmed by Williams (1980) who stated that fungi must
have moisture and therefore do not attack wood that is dry.
In addition to moisture, wood rotting fungi also prefer warm
temperatures of between 20 -30ºC for optimum development and
5
this explains why wooden hive components decay readily in the
tropics if left unprotected.
Paint can protect the
surface
When a beehive is painted, it is covered with a protective film. The
film (paint cover) protects the hive from the elements (weather and
sun) and keeps the moisture (rain and dew) on the outside. As a
result, the timber remains dry and is not prone to decay.
A broken paint film, such as cracked paint, will allow entry of
moisture into the wood. The moisture remains trapped by the more
or less sound paint cover and provides a favourable environment
for wood rotting fungi and eventual decay of the wood. Damp
timber protected to a greater or lesser degree by a deteriorating
paint film will dry more slowly than that unpainted wood.
Mechanical damage to
painted hives
Wooden hive parts and paint cover can suffer considerable damage
that results from:
• transport of hives
• use of hive tools to separate boxes
• fastening of hives with metal straps
• dumping of boxes on the ground to dislodge bees.
Physical damage of this type to wooden hive parts will rupture the
paint and provide opportunities for water to enter the timber and
become a catalyst for decay.
Environmental effects on
wood
In addition to the physical damage described above, environmental
factors can also have an adverse effect on timber. These effects are
described by Weatherhead and Kennedy (1980). Sun, wind and
rain can cause physical degradation of timber. A change in the
moisture content of the timber can lead to expansion or contraction
and this in turn leads to warping and splitting.
Successive wetting and drying of timber also causes a loss of
natural oil and waxes leaving the timber exposed to the effects of
moisture. This process can be controlled by water repellent
treatments that penetrate into the timber and repel water. Less
water enters the timber and this reduces the degree of expansion
and contraction.
Where the moisture content of the wood remains relatively constant
there is only minor (minimal) swelling and shrinkage particularly
around the joints. Some re-treatment of the timber may be required
from time to time to ensure adequate protection.
6
Successful hot wax dipping The key to successful hot wax dipping is to have the timber very
hot. At this point, the moisture, sap and air in the timber is
replaced by molten wax. One apiarist advised: ‘If you don’t heat
your timber to the same temperature as the wax you won’t dry it
out’.
Hot wax as a preservative A timber preservative for beehives must have good water
repellency and no adverse effect on bees. Hot wax dipping using
paraffin and microcrystalline waxes has both of these qualities.
Efficacy of hot wax dipping. Robinson and French (1984) indicated that some apiarists found
that hot wax dipped treatments lasted in excess of 15 years before
retreatment of the material became necessary. Some beekeepers
have indicated that well-treated boxes will last for more than 20
years before further treatment is required.
The extent of microcrystalline wax penetration was determined in
trials conducted in Australia by Robinson and French (1986).
They exposed blocks of wood to microcrystalline wax coloured
with a wax soluble dye and placed in an oven at 135ºC for one
hour. The dye was just visible in the latewood at 2 mm on the
radial face and up to 5 mm on the tangential face. These
experiments do not fully replicate the environment provided by a
vat of hot wax because the temperatures used in the trials was well
below that recommended for hot wax dipping. Therefore the above
findings should be treated as a guide only.
Some reports indicate that during hot wax dipping, the heated wax
may penetrate up to about 50 mm in the end grain of timber.
During dipping, the molten wax penetrates the joints, repaired
sections and other surfaces of the box. The hotter the wax is, the
greater penetration of wax is likely to be achieved.
As previously indicated, apiarists have stated that dipped items will
last for many years without further treatment. Unfortunately, there
appears to be no comprehensive study to determine the
effectiveness of hot wax dipping under Australian conditions. Wax
dipping in New Zealand is reported by Tew (1984) who indicated
that sap timber, the portion of timber that would normally decay
after a few years, should last as long as 10 years if re-dipped at 3-4
year intervals. However, he did not indicate the length of time that
the timber was dipped and it is probable that the dipping time was
insufficient.
The majority of apiarists who dip hive components choose to paint
the material as soon as possible after it has been removed from the
vat and while it is quite hot. The paint is sucked or drawn into the
hot timber as it cools. It is thought that the paint adds extra
protection to the timber by preventing or reducing the leaching of
wax over time. A light coloured paint will also help to protect
hives from overheating in the summer sun.
7
3. Safety
Precautions
Hot wax dipping can be dangerous if safety procedures are not
followed. If used carelessly, hot wax dipping can result in:
• severe burns to the operator
• headaches and drowsiness from fumes
• fire.
Material Safety Data Sheet
(or MSDS)
Always ask for and obtain a Material Safety Data Sheet (MSDS) for
each type of wax you buy for dipping. The sheet is prepared by the
manufacturer of the wax and contains detailed information on
precautions for safe handling, use and any health hazard. It will also
provide essential information about the flash point of the molten
wax.
Read the MSDS Take time to read the Material Safety Data Sheet and follow all
safety directions.
Employee safety
Any employee who is to conduct hot wax dipping must be provided
with a copy of the Material Safety Data Sheet and adequate
protective clothing. Employees should also receive training in hot
wax dipping procedures. Confirm that the employee has read the
Material Safety Data Sheet and understands your directions.
Confirmation that the employee has obtained the necessary
competencies can be obtained by asking the employee to demonstrate
the skills and knowledge that the training was expected to provide.
Safety equipment
Accidents can happen unexpectedly!
Hot molten wax can splash and burn the operator. Beware of drips
of wax draining from an item as it is removed from the vat. Make
sure you or any other operator is fully clothed and protected.
Protective clothing and safety items include:
* coveralls * hat
* leather gloves * apron
* face shield * protective footwear.
First Aid - be prepared
Molten wax can cause severe burns to the skin. If a burn is received
from hot wax or direct contact with the hot vat, run cold water over
the burn for at least 15 minutes. One apiarist visited by the author
had a drum of water ready nearby for such emergencies.
Obtain medical assistance and advice as quickly as possible if the
operator receives burns.
8
Hazards . . . . .
Where to dip?
Indoors or outdoors?
Carrying out wax dipping operations in-doors can be extremely
dangerous. The hazards arising from this practice involve:
• fumes
• fire.
Avoid fumes given off by the molten wax. They are dangerous!
More about fumes – how
good is the ventilation?
Ensure good ventilation is provided throughout the dipping
operation. Apiarists conducting hot wax operations have reported
severe headaches.
Hot wax dipping should only done outdoors. If you choose to hot
wax dip in a purpose built shed or similar semi-enclosed area, you
will more than likely experience the effect of a build up of dangerous
fumes.
Even apiarists using large vats of molten wax outdoors have reported
that they have sometimes become effected by fumes.
Fire - Beware! Detailed notes on fire prevention are presented in the next section
‘Fire safety’.
9
4. Fire safety “Observe all safety precautions and wax dipping can be done safely”
Be fire conscious
no complacency please!
Please familiarise yourself with the points below. Develop a fire
safety plan and you will be prepared for any emergency.
Remember, that if a fire gets away from your premises you will be
liable for damage to other people’s property.
The Country Fire Authority of Victoria provided much of the
following information.
No complacency please! An apiarist whose vat of wax caught fire
reported flames as high as 10 metres in the air!
Don’t leave molten wax
unattended
Always keep a watchful eye on the molten wax. A number of
apiarists’ sheds and equipment have been destroyed by fire, as a
result of wax melting operations, particularly when molten wax,
including molten beeswax, has been left unattended. Such cases
have included hot wax dipping operations.
Local fire brigade Know the telephone number of your local fire brigade and have it
handy in case of emergency. Preferably, have a mobile phone on
hand. Check that the mobile phone will operate in the area.
Fire regulations Familiarise yourself with fire regulations. Observe local fire
regulations at all times. Take note of days of Total Fire Ban and
declared Fire Danger Periods.
Some fire regulations require that there is no combustible material
within 3 metres of the vat during the declared Fire Danger Period.
It is suggested that apiarists confirm these details with the local fire
brigade.
Flash point - Danger!
Don’t over heat the wax
A flash point is the temperature at which the molten wax will
spontaneously ignite.
Never allow the temperature of the wax to get close to, or exceed the
flash point printed on the Material Safety Data Sheet. (Refer also to
section ‘Waxes for dipping’).
A representative of a firm supplying waxes to apiarists has advised
that temperature the wax should not exceed 180ºC. At the very least,
a safety margin of 20-30ºC below the flash point should be observed.
Overheating the wax may cause a ‘boil-over’ (See below).
10
When removing a dipped item from the vat ensure wax does not drip
on the gas burner.
Fire fighting equipment
The following items should be ready for use in case fire occurs:
• a dry chemical powder fire extinguisher - to extinguish fire
burning the wax
• a hose connected to a water supply - to extinguish fire that may
have spread to nearby vegetation, sheds, beehive components or
other combustible material.
Note: Water must not be used on molten wax.
Maintain fire fighting equipment in good working order and ensure it
is close-by and readily accessible during dipping operations.
‘Boil-overs’ - what
happens?
Beware of damp wood
A ‘boil-over’ may occur when molten wax froths and bubbles
excessively, rises to the rim of the vat and spills over the sides. A
boil-over is extremely dangerous because it may lead to fire. Boil-
overs may be caused by:
• overheating the wax
• moisture in the timber - make sure the material is dry internally
before it is dipped.
Some hardwood sheets (eg masonite) can cause high levels of
frothing. It is suggested that only small quantities of hive
components made of this material be dipped at any one time.
Some operators have found that if excessive frothing occurs when an
item is placed in the molten wax, immediate removal of the item may
remove the risk of a boil-over.
A potential boil-over may be indicated by the development of large
bubbles while an item is submerged in the wax.
‘Boil-overs’ - follow your
fire safety plan! If a boil-over occurs, immediately cut the heat source by turning off
the gas or electricity. This action is the first step to prevent a fire.
If the boil-over causes the wax to ignite, the fire may be smothered
by:
• using a dry chemical powder extinguisher first
• an industrial size fire blanket
• a tight fitting vat lid. For operator safety, this should only be
applied mechanically. It would be dangerous to move close to the
fire to place the lid on the vat.
Note: never apply water to extinguish fire burning the wax.
11
Fire prevention - some
simple steps before dipping
is commenced
Fire may result from poor maintenance and failure of equipment.
Before commencing wax dipping operations observe the following:
• inspect all electrical items for frayed cords and broken fittings
• use only heavy duty electrical cords and unwind any coils to
prevent them from overheating
• test the thermostat at least once before starting the season’s
dipping - failure of a thermostat can result in the overheating of
wax
• check the vat to ensure all welds are sound and no leakage of
molten wax is possible.
Where are the controls
situated?
When setting up your wax dipping operation, make sure the gas
bottle and electric switch are not attached to the wax vat or
positioned immediately adjacent to it. Should a boil over or fire
occur you will need to turn the controls off. The controls are best
placed in a position that they can reached without endangering
yourself in an emergency.
Where to place the gas
bottle
Ideally, the gas bottle should be placed 3-4 metres from the wax
dipping unit so that the supply of gas can be turned off in the case of
a fire emergency. Make sure the unit is connected to the gas bottle
by an approved gas hose.
Readers are advised to check with the Office of Gas Safety (or
equivalent) in your State or Territory about regulations that may
stipulate a minimum distance from the point of ignition (the gas
flame) to the gas bottle.
Fire safe area
Prepare a ‘fire safe’ out-doors area that will not allow spread of fire
should an accident occur. Such areas could be concrete or bare soil.
Remove dry grass and any other flammable material in accordance
with fire regulations.
It is preferable that the area around the vat be surrounded by
bunding (similar to a small levy bank) to contain any molten wax that
might spill during a boil over. This will also help to contain fire
should the wax ignite. The bunding should be able to contain 50%
of the volume of wax originally contained in the vat.
Keep the area free of inflammable materials, including supplies of
paraffin and microcrystalline wax, at all times. Remove any wax
below or near the vat that may have accumulated as wax dripped
from hive components as they were removed from the vat.
12
5. Waxes for dipping
Suitable waxes A mixture of microcrystalline wax and paraffin wax is commonly
used by Australian apiarists.
Both microcrystalline and paraffin waxes are sold separately and are
mixed by the apiarist to form a 50/50 mix by weight. The two
waxes are sold in either slab (block) or bead (pastille) form
depending on the grade of wax.
In Australia, paraffin wax is generally not used on its own. The
following scenarios can be expected if material is dipped solely in
paraffin wax:
• the surface of the dipped item may become very sticky in the
summer sun and can readily collect dirt and grime
• paint may not readily adhere to the surface of the treated item.
Microcrystalline wax may be used on its own, but few apiarists do
this.
Photo 4. Microcrystalline beads (or pastilles) (left) and block of
paraffin (right).
Other additives Some apiarists add a small quantity of beeswax and/or linseed oil to
the 50/50 microcrystalline and paraffin wax mixture. It is believed
that the addition of a small amount of one or both of these items
further increases the life of hot wax dipped timber. The author has
been unable to confirm whether this is true and to determine the
exact quantities of these additives used by these apiarists.
Beeswax and linseed oil cost more than microcrystalline and paraffin
waxes. Unless it can be shown that these additives can increase the
life of the timber, there is no economic benefit to be gained in using
them.
Flash points - check the
Material Safety Data Sheet
Always consult the Material Safety Data Sheet for information about
flash points of waxes to be used in hot wax dipping.
13
Allow a safety margin with
flash points
Remember, never allow the temperature of the wax to get close to or
exceed the flash point.
Always allow a safety margin. The temperature of the wax should
always be 20-30ºCelsius below the flash point.
Note: The flash point of a 50/50 mix (by weight) of microcrystalline
and paraffin wax must have a flash point of 220ºC. The flash point
of the combined waxes is dependent on the grade and mix of the
waxes and will be lower than the average of the flash points of the
two individual waxes.
Refer to the safety data material sheets for information on the flash
point of the waxes. Alternatively, obtain this information from the
firm from which you purchased the wax.
What temperature?
Some apiarists use 140ºC when using wax dipping for preservation.
For effective sterilisation of hive components, the temperature of the
wax should be in the range of 150° to 160º Celsius. There is no need
to exceed this temperature.
A representative of a firm supplying waxes to apiarists has advised
that the temperature of the wax should not exceed 180ºC.
14
6. Hot wax dipping for preservation “The key to successful hot wax dipping is to have the timber thoroughly heated throughout
without exceeding the safety precautions detailed in this manual”
Hive material that should
not be dipped
Plastic items may warp or melt and consequently supers and queen
excluders made from this material are unsuitable for dipping. This
also applies to vinyl hive mats and plastic items found on some bee
escape boards and hive lids. Plastic items like these should be
removed before dipping commences.
Preparation of material to
be dipped
Apiarists use a variety of methods to prepare previously painted hive
components for dipping. Examples are:
• sanding back to bare timber
• steam cleaning to remove dirt and loose, flaking paint
• high pressure water treatment to remove dirt and loose, flaking
paint.
Photos 5 and 6. Applying high pressure water treatment to supers
(left) and cleaned supers with loose paint removed prior to dipping
(right).
Note: If you use water to clean material, allow sufficient time for it
to thoroughly dry before dipping it in hot wax. Failure to observe
this will result in excessive frothing of the wax.
Some apiarists choose not to remove existing paint before dipping an
item. They usually scrape off any blistered paint before the new
paint is applied to the item while it is still hot.
Thermometer and timer Use a thermometer and timer to correctly measure temperature and
period of dipping respectively.
A digital hand held thermometer is suitable for this purpose. An
emersion probe, usually 300 mm in length, is attached to the
thermometer unit. Emersion probes can also be custom made to any
length to suit any size vat.
Use the thermometer regularly to ensure the correct temperature is
maintained throughout the dipping process and is not exceeding
safety levels.
15
Starting up!
Melting and heat the wax
When starting up, operators use a gentle heat to begin melting the
wax. For example, only one of the three gas rings will be lit until
such time as molten wax is observed rising to the top of the solidified
cake next to the walls of the vat. This initial gentle heating prevents
undue frothing and sudden expansion of the wax thereby protecting
thermostat sensors, if present, inside the vat. It also allows liquefied
wax to fill the air space under the block of wax.
When molten wax is seen at the edge of the top of the cake more heat
may be applied within the safety limits.
Approximately 2-3 hours may be required to liquefy all the wax in a
vat that has a capacity to hold one or two supers. The heating time
for a vat that contains 4-6 supers is approximately 5 hours.
A useful suggestion! Plan to conduct the wax dipping operation over
several days rather than the odd day here and there. The wax may
remain warm to hot overnight and will require less heating and time
to reach the desired operating temperature the next day.
Maintaining temperature When all the wax is liquefied and the desired temperature is reached,
the heat source may be turned down as there is only a need to
maintain the temperature. For example, where four barbeque
burners (jets) are used to boost temperature after the initial heating,
only two will usually be required to maintain the desired
temperature.
Careful dipping – no
splashing!
Lower the hive part carefully into the wax to avoid splashing.
Use a weight to fully
submerge the item
The item will want to float near the surface of the wax and will
probably not be fully submerged. A weight is used to push the
item(s) below the surface of the molten wax. Here are a few
examples of methods used by apiarists:
• a lever and clamp (see photo 14)
• an old beehive box placed on the item to weight it down - a heavy
metal bar on top of the old box will add extra weight
• a variation of the above method has about 6-8 nails placed in the
bottom edge of an old bee box. The protruding nails allows the
wax to freely flow around the top edge of the box being dipped
• where supers are fitted with Reade clip fasteners, several may be
fastened together. The top box although not being dipped is used
firstly as a weight and secondly as a means of lowering and lifting
the clamped supers in and out of the vat (see photo 9).
• a metal grid (eg, an oven tray) is placed over the item being
dipped and is pushed below the surface by a sturdy piece of wood
Whatever system is used to weight the material being dipped, care
must be taken to make sure it is sturdy, reliable and won’t fall into
the wax.
Time of dipping After interviewing a number of apiarists, the author has come to the
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conclusion that for best results, material should be dipped for 10
minutes.
Apiarists believe that the longer an item is dipped and the hotter the
timber becomes, the greater the absorption of wax into the timber.
Frothing and bubbling! The hot molten wax penetrates the wood and replaces the moisture
and air in the timber. The moisture is boiled off. The process is
similar to the cooking of potato chips in hot oil.
Photo 7. A vat of molten wax ready for dipping of hive material.
Note: Hot wax dipping should not be done in an enclosed space.
The owner of this vat plans to increase the head space between the
surface of the wax and the rim of the vat. This will improve the
safety margin in case of a boil over (refer to section on vats).
Photo 8. Some frothing occurs when a hive component is placed in
the molten wax.
Photo 9 As the hot wax penetrates the timber and expels much of
the moisture and air, the frothing reduces in intensity.
17
Remove the item for
draining
Remove the item from the vat and place it on the drain tray to allow
excess wax to drain back into the vat.
Apiarists find that very little, if any, wax drains from timber items
that have been thoroughly heated during the dipping process.
Consequently, a drain tray is not necessary.
When the weighting device is removed, the item in the vat will
partially float above the surface of the wax and can be lifted out.
Pick-up and removal of very hot material may be facilitated by:
• wearing thick leather gloves
• using pliers or tongs to grasp the item
• using two pieces of timber each having at one end several nails
with pointed ends protruding. The ends of the boards with
protruding nails are placed in the handholds of the dipped box
which is then lifted out of the vat.
Which ever means is used to lift the item from the vat, make sure the
item cannot fall back into the molten wax to cause splashing.
Allow the surface of the item to cool a little and then remove the item
to a separate area for painting.
Photo 10. Three Ideal supers fitted with Reade clips may be
fastened together and dipped and lifted as one unit. The top super is
never completely immersed in a single box vat and clips attached to
this box may be safely grasped by the operator. After dipping each
batch of three boxes, the bottom two boxes are removed for painting.
The top is then placed at the bottom of the next stack of three for
complete immersion.
Draining hive lids Migratory hive lids are best dipped after the after the metal cover has
been removed. This is because wax may be trapped between the
metal and inner cover if the lid is left intact. In hot weather, the
solidified trapped wax may melt and seep down the external walls of
the hive.
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After removal from the vat, hive lids are best placed on an incline of
45° to the draining tray so that one corner is lower than the others.
This is particularly important if the metal cover has not been
removed, as positioning lids in this manner allows excess wax
trapped between the inner and metal covers to drain away. It pays to
wipe wax from the metal cover before painting and while the hive lid
is still hot.
Painting While the item is hot it may be painted. In fact, the hotter the item
is, the better it is for painting. Paint is almost literally slapped or
brushed onto the hot item. The paint is drawn or sucked into the hot
timber as it cools. (See notes on ‘Paints and painting’).
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7. Hot wax dipping for sterilisation “Use the correct time and temperature to ensure disease contaminated components are
sterilised”
A successful way to sterilise
some AFB contaminated
hive parts
AFB contaminated hive parts can be sterilised and made safe for
reuse by hot wax dipping.
During the process, spores of American foulbrood are either:
• killed (made non-viable) by exposure to heat
• encapsulated within the wax.
Its been used for over 30
years
New Zealand apiarists have used hot wax dipping to sterilise hive
parts contaminated with American foulbrood spores (Paenibacillus
larvae) for over 30 years. Experience showed that the process was
effective. However, it was not until 1998 that Goodwin and Haine
conducted research and proved that hot wax dipping, when used
correctly, would render all AFB spores non-viable.
Time and temperature Minimum time of dipping: 10 minutes
Minimum temperature range: 150° - 160º Celsius
These recommendations are based on research conducted in New
Zealand by Goodwin and Haine (1998).
Using the above time and temperatures will ensure you successfully
sterilise the components you have dipped.
Reduced periods of time and lower temperatures than those stated
above will result in some AFB spores remaining viable and 100%
sterilisation will not be achieved.
Thermometer and timer Use a thermometer and timer to correctly measure temperature and
period of dipping respectively.
A digital hand held thermometer is suitable for this purpose. An
emersion probe, usually 300 mm in length, is attached to the
thermometer unit. Emersion probes can also be custom made to any
length.
Use the thermometer regularly to ensure the correct temperature is
maintained throughout the dipping process and is not exceeding
safety levels.
Submerge the hive part
All items to be sterilised must be fully immersed in the wax for at
least 10 minutes to ensure effective sterilisation.
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What hive parts may be
sterilised?
The following items may be dipped:
* wooden bottom boards * supers (with clips)
* hive lids, * nucleus boxes
* feeders * metal queen excluders
* bee escape boards without plastic or fine mesh inserts.
Hive parts unsuitable for
dipping
Frames, combs and hive mats from AFB infected hives should be
destroyed by burning or irradiated as appropriate and in accordance
with State regulations. Hot wax dipping of these items will only
contaminate and dirty the molten wax.
Plastic items may warp or melt and consequently supers and queen
excluders made from this material are unsuitable for dipping. This
also applies to plastic items found on some bee escape boards and
hive lids. Plastic items like these should be removed and should be
disposed of in a careful manner keeping in mind that they originated
from hives infected with AFB.
Preparation of hive parts
prior to dipping
All internal and external hive parts should be cleaned before dipping
to remove:
• loose and flaking paint
• beeswax including brace comb, propolis, honey and dead bees
• other debris as found on bottom boards.
This cleaning only removes debris that could soil and contaminate
the hot wax and reduce its useful life.
Note: Wax and other debris scraped from AFB infected components
pose a significant disease risk and must not be exposed to any bees.
It should be disposed of carefully in accordance with State or
Territory apiary laws.
When to start dipping Dipping may be commenced as soon as the wax reaches 150° - 160º
Celsius.
Bee-proof environment
required
Hive parts removed from AFB infected hives should be stored in a
bee-proof environment to prevent spread of the disease.
When it is time to commence dipping, infected items should be
brought out in small numbers and kept covered so that bees can’t
have access to them. The handling of diseased items must be done in
accordance with appropriate State or Territory legislation.
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8. Vats for hot wax dipping “Safety and efficiency are the main issues to consider when designing a system”
Construction of the wax vat The vat that holds the molten wax may be made from 3 mm black
steel plate or stainless steel.
In New Zealand, the bottom of the vat is constructed of 6 mm steel
plate and the sides of 3 mm steel plate (Matheson 1980). The pieces
of plate are welded together on both sides for added strength to
prevent them from rupturing. Alternatively, the vat could be
constructed from one piece of steel plate and this would reduce the
number of joints to be welded.
A cover or lid is constructed using metal 1.6 mm thickness.
It is suggested that before constructing a vat, apiarists consult an
engineer for expert advice.
Size of the vat The vat should be large enough to accommodate the largest hive
component to be hot wax dipped. In most cases, the largest item (at
least on a plan view) would be the hive bottom board which often
has a protruding lip or landing platform which makes it longer than a
hive box.
Some vats are made to accommodate to 1, 2, 4 or 6 beehive boxes.
Photo 11. A vat, with drain tray, suitable for dipping one super at a
time. The unit is heated by gas supplied through four independently
adjusted barbeque gas burners. Note that for safety reasons, the gas
bottle should be position away from the unit and the vat itself should
be located outside the shed. (Refer to section on ‘Safety’).
Depth and safety
considerations
-prevent boil overs!
The vat should have sufficient depth to allow for:
• a full depth hive box to be fully submerged in the molten wax
• displacement of wax when items are submerged
• excessive frothing and bubbling.
The height of the walls of a unit designed for dipping one box at a
time should provide a safety margin of at least 230 mm above the
level of the molten wax. One unit observed by the author had a
22
safety margin of 155 mm - this had not been sufficient to contain a
boil-over.
A 4-box vat observed by the author had a safety margin of almost
400 mm in the height of the walls above the level of the wax in its
solidified state.
Photo 12. The same vat (as in photo 11) showing dipped super on
drain tray and molten wax. Note the distance from the wax to the
top of the extended sides - a safety feature designed to contain wax
boil overs.
Safety margins - include a
rim above the level of the
wax
Another vat observed by the author had a safety margin and
incorporated an extended rim. It comprised of 80 mm on the
perpendicular walls of the vat plus an extension of another 250 mm
in height. The steel plate used for the extension was placed on an
angle of 45º outwards from the walls of the vat.
Size of a single box unit The suggested dimensions for a vat capable of holding one-box are:
* length 596 mm
* width 373 mm
* depth 575 mm
The bottom of the vat is 320 mm from ground level.
Plans for 4 or 6 box units A 4 or 6 box wax dipping unit measuring 1151 mm x 793 mm (plan
view) is operated by John Sunderland of Sunderland Apiaries. This
unit has insulated double walls to increase efficiency. A chimney is
also provided. Readers requiring more information on this unit
should contact Sunderland Apiaries, Dubbo, NSW, direct.
Photo 13. The vat operated by Sunderland Apiaries, Dubbo. Note
the head space from the wax to the top of the walls. Note also the
gas hose (bottom left) which is connected to the gas bottle located
over three metres from the unit.
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Four boxes are placed in the vat in such a manner to form two stacks
of two boxes. A third box, turned on its end, is then placed within in
each stack, to provide a total of six boxes being dipped at any one
time. The boxes are kept submerged in the molten wax by use of
clamps.
Photo 14. The clamps are used to keep the supers submerged in the
molten wax.
The unit is gas heated using 4 burners removed from Donarch space
heaters.
Safety with electrical
equipment
Thermostat and electrical connections are best covered with a metal
flap, cap or hood to protect them from the weather and possible boil
overs. Such protection can help to alleviate the risk of electrical fire.
Use a lid A tight fitting lid for the vat is recommended by Warhurst and
Goebel (1995). It can be used to smother flames should the wax
catch fire. The lid should be able to be lowered mechanically in the
event of a fire emergency. In this way the operator need not get
close to the fire.
Photo 15. Wax dipping unit with lid in place.
When the vat is not in use, the lid should be in place to prevent entry
of dust and rain that could lead to rusting of the metal components.
Remember that moisture in the vat can cause the wax to froth
excessively when it is next heated.
24
Photo 16. This vat is capable of dipping four supers at a time.
Supers are removed from the wax and placed on two metal cross
beams to allow excess wax to drain. The vat is partially insulated
with aluminium sisalation and bricks. Completion of the brickwork
would greatly improve the insulation and prevent heat loss.
Sources of heat
Gas or electricity may be used to heat the vat. The author strongly
suggests that apiarists who plan to build a wax dipping unit should
consider electricity as the preferred heat source because there is no
naked flame.
Solid fuel fires should not be used because of the difficulty in
controlling the fire and amount of heat applied to the vat. When
accidents happen, gas and electricity can be quickly switched off.
Gas Readers are advised to consult a registered gas fitter for expert
advice on the use of gas to heat hot wax dipping units.
Barbeque burners and gas rings are often used. It is strongly
recommended that vats be fitted with appropriate thermocouples and
thermostats to regulate the flow of gas and consequently the
temperature of the molten wax. At the very least, it is advisable to
have each gas burner with its own independent tap to enable efficient
regulation of the flow of gas and the amount of heat to be applied to
the vat at any given time. Gas ring units incorporating three
independent rings each with its own tap also enable the flow of gas
to be regulated.
Photo 17. Four gas burners are used to heat the unit operated by
Sunderland apiaries.
Electricity Readers are advised to consult a registered electrician for expert
advice on the use of electricity to heat hot wax dipping units. An
electrician will provide advice on suitable thermostats and electric
25
heating coils to be placed under the steel plate base of the vat.
Insulating the vat The vat may be insulated to:
• increase efficiency of the unit by minimising heat loss
• protect the operator from accidental burns.
Insulation can be provided by using:
• several layers of ordinary building sisal wrapped around the vat.
The vat is then bricked-up to provide additional insulation and
protection from cold winds (See photo 16)
• 25 mm semi rigid aluminium foil backed heat resistant fibreglass
sheet between double walls of the unit.
Draining tray The metal draining tray, if required, should be big enough to hold the
largest hive component and is usually positioned at one end of the
vat. Excess wax drains from the dipped item, onto the sloping tray
and flows into the vat (See photo 12).
The use of baffles to raise the dipped item from the floor of the tray
will ensure better drainage of wax from the dipped item.
A couple of metal pegs welded to the floor of the tray near the vat
will prevent dipped items sliding back into the vat.
Drain tap Over a period of time, wax in the vat will become soiled by:
• a build up of dirt, paint and other debris
• oxidation from the metal vat.
It may be necessary to remove soiled wax and replace it with new
wax to ensure that dipped hive material is clean. A drain trap is
used to drain dirty molten wax from the vat. In the case of
oxidation, the contaminated wax will sink to the bottom of the vat
and only that portion of the wax will need to be drained out.
Large debris can be removed from the molten wax using a scoop.
Moving the vat Wheels may be attached to one end of the small vat to enable it to
moved to a storage area when it is not in use.
26
9. Paints and painting
Reasons for painting dipped
material
Hot wax dipped material may be painted to:
• add further protection to the timber
• reduce leaching of wax from the timber
• provide a cooling effect for the hives in the hot weather
• provide a neat appearance.
In summer, honey colonies cope much better with the hot sun and
high temperatures when their hives are painted with light colours.
When hot wax dipped material is not painted, hive bees tend to
cluster on the front of the hive where the air is cooler.
Some beekeepers choose not to paint hot wax dipped material
believing it is unnecessary. However, a little time spent in painting
may be good insurance against colony stress in normal summer
temperatures and possible melt down of combs in extreme heat.
Paints and their adhesion
on wax dipped material
The key to successful paint adhesion is to have the dipped material
as hot as possible. When applied to hot treated wood, the paint is
pulled or sucked into the timber as it is cools.
Dipped items that have cooled cannot be painted successfully. The
paint will not be sucked into the timber nor will it adhere well to the
cooled wax. It appears that this process of the paint being pulled or
sucked into the timber may significantly diminish or cease if the
temperature of the dipped item falls below 130ºC (Griffiths 1992).
It is best to apply paint after the dipped material has been allowed to
quickly drain but while it is still very hot. One apiarist quickly
wiped any excess wax adhering to the dipped item before applying
paint.
Painting is made easier when the items to be painted are placed on a
rotating painting stand.
Oil based or acrylic paints? Most apiarists interviewed by the author preferred to apply oil based
paints. They use one of the following:
• two coats of gloss enamel applied to the dipped item while it was
still very hot. Because the first coat is quickly drawn into the
timber, a second coat can be applied almost immediately
• undercoat applied to the dipped item while it was still very hot; a
coat of gloss enamel applied later when the item had cooled and
the undercoat had dried.
Where acrylic paint was the preferred paint, two coats were applied
while the dipped item was still quite hot.
Those who used oil based paints considered the paint to wear better
27
and last longer than acrylic paint. It was generally considered that
acrylic paint tended to rub off easily, and in hot weather, surfaces
with acrylic paint would tend to bond together causing hive
components to stick to each other.
What surfaces to paint? Apiarists differed widely in their approach to painting a dipped item.
Some painted all surfaces while others painted only the external
surfaces. The only majority agreement was that surfaces to be
painted should have two coats of paint.
Reason for paint not being
drawn into the wood
If the paint is not drawn into the timber it is likely that the wood was
not sufficiently heated throughout when it was dipped. It may be
necessary to increase the time of dipping or increase the temperature
of the wax within the safety limits to ensure the wood is thoroughly
heated.
How many coats? Usually two thick coats of paint are applied. One apiarist applied a
third coat on the top edge of the hive box for extra protection.
Photos 18 and 19. A revolving stand is useful when painting dipped
supers which are very hot.
Blistering of previously
applied coats of paint
During the dipping process, some blistering of paint may occur on
items that have been previously painted.
After draining, the blistered paint should be quickly and immediately
scraped off before applying a new coat of paint to the still hot
component.
28
10. References
Goodwin, M. and Haine, H. (1998). Using paraffin wax and steam chests to sterilise hive parts that
have been in contact with colonies with American Foulbrood Disease. New Zealand Beekeeper.
5:4, 21.
Griffiths, G. L. (1992). Protocol for wax dipping bee equipment. In Preservation of wooden hive
equipment. Miscellaneous Publication 4/92 March 1992. Compiled by L Allan, Senior
Apiculturalist, Department of Agriculture, Western Australia.
Kalnins, M. A. and Detroy, B. F. (1984). Effects of wood preservative treatment on honey bees and
hive products. Journal of Agricultural Food Chemistry. 32:1176-80
Matheson, A. (1980). Easily constructed paraffin wax dipper. 41:4, 11-2.
Robinson, P. J. and French, J. R. J. (1984). Beekeeping and wood preservation in Australia.
Proceedings of the 21st Forest products research Conference, November, 1984. Volume 1.
Robinson, P. J. and French, J. R. J. (1986). Beekeeping and wood preservation in Australia. The
Australian Bee Journal. 67:1, 8-10.
Tew, J. (1984). Paraffin wax dipping of hive equipment. Gleanings in Bee Culture. 112:8, 422 and
426.
Warhurst, P. and Goebel, R. L. (1995). The bee book: beekeeping in the warmer areas of Australia.
Page 35.
Weatherhead, T. F. and Kennedy, M. J. (1980). Adhesives and wood preservatives for the beekeeper
in the 1980s. The Australasian Beekeeper. 82:4, 88-94.
Williams, D. (1980). Preserving beehive timber. New Zealand Beekeeper. 41:4, 13.